In existing sewing machines for blind-stitch, the work piece is pushed up by a cloth lifting means adapted to press the cloth against an upper pressure plate. In the current sewing machine art, the upper pressure plate is disposed adjacent the sewing portion and along the feed direction of the cloth, in order to optimize the cloth pressing effect.
Further, in the hem stitch of a thin cloth, the hem pulled by a sewing thread curls easily. In order to prevent curling, a seam stabilizing piece like a springboard may be provided in the same manner as the upper pressure plate. Thus, since the current sewing machine for blind-stitch has to provide the cloth pressure plate or the like near the sewing portion, the looper of the blind stitch machine has its motion limited so as to not collide with the cloth pressure plate or the like. Consequently, the looper operates the sewing thread only by partial oscillation and can not form complicated seams.
Accordingly, in a cloth which is easily frayed, the hem stitch and the blind stitch must be done separately. Since the seam can not be formed by a sewing machine adapted for blind stitch, it has been essential to have two working processes that make first the hem stitch with an overlock sewing machine and then the blind stitch with the sewing machine for blind stitching. The present invention overcomes the necessity for performing separate operations, and provides a better finish on the seam than is available from separate operations.